The question that Twitter's CEO asks at every product meeting

Twitter has received a generous share of criticism lately. Its stock crashed after a disappointing Q1 earnings report. Early investor and fervent Twitter-cheerleader Chris Sacca posted on his blog that he's prepared to start writing more critically about the company. CEO Dick Costolo has dealt with analysts and Wall Streeters saying he could be out by the end of the year (something he says he's not worried about).  On stage at at Re/Code's Code Conference this week, Costolo gave some insight ...